what parameters to imagemagick will convert from EXR to PNG that matches how blender interprets the RGB values?
The short answer is that EXR holds data. In the case of visual data, it is a convention that the visual RGB data is stored in a linearised format.

When encoded as a linearised format, there is no idea of what transfer function is embedded into the data. This means that the imager has to apply the proper transfer function that covers the proper range of data within the EXR.

If you are using the "Default" rendering view, which is the sRGB EOTF, you can identify the different transfer functions and have ImageMagick convert appropriately with something like:

convert myexr.exr -colorspace RGB -colorspace sRGB mynonlineartiff.tiff


If you are using any transfer function other than the sRGB EOTF, the process would require further effort, and in most cases, ImageMagick would be an unacceptable tool to harness. OpenImageIO and OpenColorIO would be more suitable.